The inventive concepts generally relate to electronic devices, and more particular, the inventive concepts relate to non-volatile semiconductor memory devices, systems including non-volatile semiconductor memory devices, and methods of programming non-volatile semiconductor memory devices.
A variety of different types of non-volatile memory devices are known, including, for example, mask read-only memory (MROM) devices, programmable read-only memory (PROM) devices, erasable programmable read-only memory (EPROM) devices, and electrically erasable programmable read-only memory (EEPROM).
Developed from EEPROM technology, the NAND flash memory device has become widely adopted for non-volatile mass data storage applications. For example, NAND flash memory devices are commonly employed to store audio, image and/or video data in a myriad of different types of host devices, such as computers, mobile phones, personal digital assistants (PDAs), a digital cameras, camcorders, voice recorders, MP3 players, handheld personal computers (PCs), game consoles, facsimile machines, scanners, printers and so on.
Depending on the number of bits stored per memory cell, NAND flash memory devices are generally classified as either single level cell (SLC) devices or multi-level cells (MLC) devices. SLC devices store a single bit of data in each NAND flash memory cell, whereas MLC devices store 2 or more bits of data in each NAND flash memory cell.
In conventional nomenclature, the NAND flash memory cells connected to a same word line store one on or more “pages” of data. In particular, in the case of an SLC device, the NAND flash memory cells connected to a same word line store one page of data, where each bit of the page data is stored in a separate memory cell. In the case of an MLC device, the NAND flash memory cells connected to a same word line store multiple pages of data, where multiple bits of the respective page data are stored in a same memory cell. For example, in the case of an “n-bit” MLC device (n is 2 or more), the NAND flash memory cells connected to a same word line store “n” pages of data, where each memory cells stores “n” bits of data of the respective “n” pages.
NAND flash memory devices are generally characterized by being programmed and read in units of a page, and by being erased in units of memory “blocks”, where each block includes a plurality of word lines (or pages) and a plurality of bit lines respectively connected to respective memory cell “strings.” Each memory cell string is typically defined by a plurality of flash memory cells connected in series between a string selection transistor and a ground selection transistor.
The entire memory block is erased prior to programming, and the programming of each memory block generally includes sequential programming of word lines from a first word line closest to the ground selection transistor to the last word line closest to the string selection transistor.